About 13 years ago, word began to circulate among historians that the archive of the Roman Inquisition was being opened to scholars. This, for specialists in the field, was an extraordinary development, the bringing down of an intellectual Berlin Wall. For decades, eminent Catholic historians, armed with letters of recommendation from the most senior Monsignor they could lay their hands on, had been refused access. Only a handful of individuals, with high-level contacts in the Curia, were successful. But from 1998, when the change of policy was officially announced, any serious academic researcher could get in.

But it does move: "Galileo facing the Roman Inquisition" by Cristiano Banti (1857)

As with the Berlin Wall, this change had much to do with the then Pope, John Paul II. But there the similarities with 1989 mostly come to an end. For although this was a liberating act for scholars, what the subsequent scrutiny of the archive mostly showed was that the Catholic Church had been troubling itself with false fears. It was almost as if the Roman authorities had themselves been taken in by the old Protestant propaganda line, believing that to open the archive would be to lift the lid on a pullulating mass of oppressive practices and sadistic torture.

Luckily, the central archive in Rome was not the only set of Inquisition records available. There were major local archives in Venice, Udine, Florence and Naples, as well as others further afield. Using these, scholars had already done much work dispelling the old myths and stereotypes. Henry Kamen's classic book on the Spanish Inquisition (a very different organisation, as it was essentially a branch of the Spanish state) had begun the task of dismantling the "Black Legend" in that country. Other writers, such as Carlo Ginzburg in his famous study of the heretical miller Menocchio, The Cheese and the Worms, had noted the Inquisition's scrupulous respect for legal process.

Historians studying the early modern witch-craze, and the trials from which most of the surviving evidence is derived, had begun to make comparisons from which the southern European Inquisitions could only benefit. Not only was the mania more severe in northern Europe, there was much more use of torture there, and more executions. In the how-to-be-an-inquisitor manuals written in Italy and Spain, while the reality of diabolism was assumed, there was also much sensible advice, warning that accusations could come from local jealousies and vendettas, pointing out that some people — especially women — might confess to invented crimes out of genuine self-delusion.

Meanwhile, historians of science had continued to worry away at the precise nature of the Inquisition's objections to Galileo's cosmology and physics. Historians of the book had done much new research on the nature of censorship in the early modern period — in particular, on the internal strains and contradictions of the system, and on the ways in which authors and publishers were able to bend the rules.

With so much work already done by the last one or two generations of scholars, and so much new material recently emerging from the Roman archive, there is a real need for an overview of the whole subject. And that is what Christopher Black, an eminent historian of early modern Italy, has now supplied, with a marvellously detailed survey of how the Inquisition operated throughout the Italian peninsula (plus Sicily, of course, and Malta, and some Venetian territories in the eastern Adriatic) from its origins in 1542 until the end of the 18th century.